Electrical apparatus



Jan. 16, 1934. J. w. ALLEN 1,943,781

ELECTRICAL APPARATUS Filed June 19, 1931 Z9 fr:

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un M 1m Mmmnmnml m INVENTOR Joseph ll/llem .I' .4 BY A APatented Jan. 15, 1934 ELECTRICAL APPARATUS Joseph W. Allen, East Orange, N. J., assignor to Eclipse Aviation Corporation, East Orange, N. J., a corporation of New Jersey Application June 19, 1931. Serial No. 545,537

11 Claims.

This invention relates to electrical apparatus, and more particularly to means for compensating for voltage variations in an electrical circuit.

An object of the invention is to provide voltage regulating means embodying novel resistance varying means operating in response to changes in the speed of a generator, or similar unit, from which the circuit receives its current.

Another object of the invention is to provide a voltage regulator of novel construction for varying the voltage across the terminals of a generator which eliminates the necessity for vibratory control means such as oscillating armatures of the character. heretofore employed for this purpose.

A further object of the invention is to provide novel mechanism responsive to the centrifugal force variations resulting from changes in the speed of a generator for controlling the output of such generator.

Another object of the invention is to provide voltage control means responsive to changes in the speed of a voltage producing unit to vary the resistance in circuit with such unit Without at any time changing the general direction of current flow.

Another object of the invention is to provide novel voltage control means which is so constructed that changes in field current and generator voltage are very gradual and proportional to that required by a given speed of the generator.

Another object of the invention is to provide a compact, efficient, durable and readily installed mechanical unit for the foregoing purposes, possessing the further advantage that its use makes it possible to dispense with all relays and electro- .magnetically operating contacts and vibrating elements.

' These and other objects of the invention will become apparent from inspection of the following specification when read with reference .to the accompanying drawing, wherein is illustrated the lpreferred embodiment of the invention. It is to be expressly understood, however, that the drawings are for the purpose of illustration only,

and are not designed as a denition of the limits,

Fig. 2 is a sectional view taken along the line 2--2 of Fig. 1;

Fig. 3 is an exploded View in perspective of certain of the elements of Figs. 1 and 2; and,

Fig. 4 is a schematic diagram illustrating the electrical effect of the device shown in Figs. 1, 2, and 3.

Referring to the drawing, and particularly to Figs. 1A and 2, the invention is shown embodied in a unit having a cylindrical outline and adapted to be secured directly to a rotatable member 6 which may be the shaft of tlhe rotor of a generator or other current producing unit, the voltage of which is toV be controlled. Preferably, the member 6 is provided with attened portions '7 extending over a portion of the circumferential surface for registry with corresponding flattened portions of the internal cylindrical surface of the hub 8 of a cylindrical member 9 constructed of suitable insulating material, the hub 8 being preferably eccentrically located thereon, as shown. Any suitable means may be employed for retaining the member 9 and associated elements, to be described, in position on the shaft 6. As shown, such means takes the form of a retaining nut 10 engaging the threaded end 11 of the shaft and bearing upon the outer surface of the hub 8 as indicated clearly in Fig. 2.

The novel means associated with the member 9 for controlling the voltage of the unit to be regiilated, preferably includes a pair (although a smaller or larger number may, if desired, be employed) of arcuate current conducting members 12 and 13, each having an outer rim of length corresponding to an arc of preferably slightly less than 180 degreesand each provided with a projecting face or ear, as indicated at 14 and 15, said ears being apertured at 16 and 17 respectively, the said apertures being located as to permit registry with the hub 8 of the member 9, and the curvature of the elements being such as to register with the outer cylin drical surface of the member 9. Moreover, the outer cylindrical surface of the member 9 is preferably cut away on opposite faces, as indicated at 18 and 19 in Fig. 3, to permit assembly of the arcuate members- 12 and 13 thereon in such manner as -to bring the faces 14 and 15 of the, latter nush with the opposite faces of the member 9, as indicated in Fig. 2. Members 12 and 13 may be secured to member 9 by any suitable means, such as machine screws 33.

The novel voltage regulating means responsive to rotation of the assembly of elements just described to vary the resistance in one of the circuits associated with the generator, further comprises a flexible current conducting medium, herein shown as a spring 22 arranged in the form of a circular coil having its ends 23 and 24 extending into recess 32 of member 9, and fastened to the upper edges of the elements 12 and 13 respectively, as indicated in Fig. 1, the coil normally resting in contact with the concave grooves or tracks 25 and 26 located on the arcuate surface of the elements 12 and 13. The coil 22 is retained in place, although permitted a proper degree of expansion radially, by the provision of a suitable enclosing portion 29 of member 9. The portion 29 is preferably in the form of an annular plate or ledge having an inwardly turned circular rim 30, on the inner surface of which is provided a concave groove or track 31 adapted to limit the radial movement of the spring 22.

Fig. 4 illustrates one method of applying the invention to an electrical circuit adapted to be fed by a generator 35 having the usual shunt and series fields, as indicated at 36 and 37 respectively; the former being across the line indicated at 38 and 39, and the latter being in series therewith. The resistance unit constituted by the spring 22 is preferably interposed in series with the shunt field 36, with suitable connections 42 and 43 acting as terminals for brushes 45 and 46, indicated in Figs. 2 and 4 as contacting the segments 12 and 13 respectively.

Assuming application of the invention in the manner just referred to, it will'be evident that with the generator rotating at normal speed, the initial tension in the resistance spring 22 will insure its remaining in contact with the grooves 25 and 26 for its entire length. This will, in turn, insure the maintenance of a short shunt across the resistance, by way of segments 12 and 13 and a few only of the turns of spring 22. In the event, however, that the generator accelerates to a speed beyond normal, the fact that spring 22, although circular in form, is rotating about a center eccentric to the axis of rotation of the generator shaft 6, will cause that portion of the resistance element which is farthestaway from such axis to be forced outward and away from the short circuiting action of the arcuate segments 12 and 13 which are, of course, of much lower current resisting quality. The resistance between the terminals 42 and 43 will accordingly be increased, due to the insertion in the circuit of that portion of the spring which has moved away from contact with the tracks 25 and 26. 'I'he result is a reduction in the field current which flows through the shunt field, and hence an increase of voltage being generated at the increased speed is presented. As the speed continues to increase, additional portions of the resistance element 22 will be forced away from the arcuate elements 12 and 13 and thereby produce further reductions in the field current, such process continuing until at maximum generated speed, and the spring 22 will be out of contact with elements 12 and 13 for its entire length, thereby inserting maximum resistance in the shunt field and insuring a value of field current to give a voltage at the high speed'substantially the same as at low speed. As the speed of the generator drops, the reverse action will, of course, occur.

While the embodiment of the invention herein shown is of decided practical merit, it is to be understood that various other changes may be made in the construction and relative arrange- `further changes may be made in the form, de-

tails of construction, arrangement of'parts, and the uses to which they are applied, without departing from the spirit of the invention or the scope of the appended claims.

What is claimed is:

1. Power supply means for an electrical circuit comprising a generator feeding said circuit, a pair of arcuate current conducting elements connected to the rotor of said generator, means for electrically connecting said elements, and means responsive to changes in the rotor speed for increasing the resistance of said connecting means, said last named means comprising a resistance unit normally in engagement with said arcuate elements and movable out of such engagement in response to speed changes of said rotor.

2. In a device of the class described, a generato'r rot-or, a shaft rotatable with said rotor, a pair of current conducting elements eccentrically mounted for rotation with said shaft, and a resilient current conducting element normally engaging said first named elements and movable partially out of such engagement in response to changes in the centrifugal force acting thereon.

3. In a. device of the class described, a generator, a shaft rotatable therewith, and means eccentricaliy mounted on said shaft for regulating the voltage of said generator in accordance with the speed of said shaft, said means comprising a resistance coil in shunt with the armature of said generator and movable radially from said shaft in response to acceleration of said shaft.

4. In apparatus of the type embodying a generator having a shunt field and a resistance in circuit therewith, means for inserting said resistance in said circuit by successive stages in response to successive increases in the speed of the generator, said means comprising a pair of current conducting segments with which said resistance makes ,contact over an area which varies with variations in speed of the generator.

5. In combination with a generator having a. shaft, and resistance means operatively connected to the shaft and the field of said generator, said means including a resistance unit disposed about an axis eccentric to that of said shaft, said resistance u nit being movable in response to changes in speed of the shaft to vary the field of said generator.

6. In a device of the class described, a generator, a shaft rotatable with said generator, a pair of current conducting elements eccentrlcally mounted for rotation with said shaft, a resilient current conducting element normally engaging said first named elements for a certain portion of its length, and means for varying the length of the engaging portion in accordance with changes in the rotary speed of said shaft.

7. In a device of the class described, a generator, a shaft rotatable therewith, and' means eccentrically mounted on said shaft for regulating 150 the voltage of said generator in accordance with the speed of said shaft, said means comprising a pair of segments in circuit with the shunt eld of the generator, and speed responsive means for inserting increased resistance between said segments.

8. In a device of the class described, a 'generator, a shaft rotatable therewith, and means eccentrically mounted on said shaft for regulating the voltage of said generator in accordance with the speed o f said shaft, said means comprising a pair of segments normally in circuit with the shunt eld of said generator, said segments being normally connected by a resistance unit of predetermined length, and speed responsive means for varying the length of such connecting resistance unit.

9. In apparatus for use with a dynamo electric machine, means for increasing the eld resistance of said machine by successive stages in response to successive increases in its speed, said means comprising a current conducting member mounted on the rotor of the machine for rota.- tion therewith, and a resistance unit connected with said member in a manner to cause movement thereof away from said member in response to variations 'in the speed of rotation of said rotor.

10. In apparatus for use with dynamo electric machine, means for increasing the field resistance of the machine by successive stages in response to successive increases in the speed thereof, said means comprising a. current conduct-ing member rotatable with said means, and a resistance unit movable away from said member in response to acceleration of said machine, said resistance unit being suiciently resilient to return itself into more complete contact with said mem--v ber when the speed of the machine is again reduced.

11. In apparatus for use with a dynamo electric machine, means for increasing the fleld resistance of the machine by successive stages in response to successive increases in the speed thereof, said means comprising a current conducting member rotatable with said means, and a re'- sistance unit movable away from said member in response to acceleration of said machine, said member being shaped so as to oppose any tendency toward a complete separation of said resistance unit therefrom.Y

`JOSEPH W. ALLEN. 

